Composition suitable for use in the production of coated sheet material



Patented Sept. 9, 1941 UNITED STATES PATENT OFFICE COMPOSITION SUITABLEFOR USE IN THE PRODUCTION OF COATED SHEET MATE- RIAL No Drawing.Original application. April 14, 1933,

Serial No. 666,222. Divided and this application July 25, 1941, SerialNo. 404,098

8 Claims.

This application is a division of our copending application, Serial No.666,222, filed April 14, 1933. This invention relates to a compositionwhich may be used in the production of a coated sheet material and to aprocess for producing the same.

We have found that a resin which is the re-- action product of rubberwith an amphoteric metal halide can be used to provide a very su periorcoating material for flexible and transparent sheet materials such asare commonly used for wrapping purposes. Two forms of this resin now onthe market are known as "Pliolite and Plioform. dissolving crude rubber,either milled or unmilled,

curve.

tions.

M. Kratz and Herman Heckel.

These resins may be produced by.

ing solvents and the resulting solution will show no tendency tocrystallize or blush on drying. This property renders these materialsparticularly adapted to high speed production where rapid drying andnon-blushing properties are essential.

It is, then, an object of this invention to provide a waterproof,transparent, and heat-sealing sheet material having a very low rate ofvapor transmission.

It is also an object of this invention to provide a process for themanufacture of such sheet material.

It is an additional object of this invention to in a suitable solvent,such as benzene to form a provide a suitable coating composition for userubber cement. An amphoteric metal halide is in preparing such sheetmaterial. then added to this solution. Tin tetrachloride is Other andfurther objects of this invention will pre ably used. A reaction takesplace which be apparent from the following specification and manifestsitself in a drop in the viscosity of the claims: solution. When theviscosity has reached a pre- A reaction product of rubber with anamphodetermined point, the reaction may be interteric metal halide whichwe prefer to use is compted and an end product may be precipitatedmercially known under the trade name Pliolite" therefrom by means ofalcohol or acetone. Prefand is an end product, probably a cyclo rubber,erably, however, the end product is isolated from obtainable by reactingrubber with stannic chlothe reaction mass by steam distillation. Resinride to form an addition product. -The stannic having slightly differentcharacteristics may be chloride is then split ofi from the additionprod- Pmduced depending upon the point at which the not to form apolymerized end product. reaction is interrupted. The name Pliolite" re-Specifically this polymerized end product may fers to a resin producedby stopping the reaction be prepared by boiling a solution ofunvulcanized at one point in the viscosity curve and the name rubber,such as pale crepe rubber, in benzene, Plioform" refers to a resinsuitable for use as a say of about 12% concentration, for two hours.molding compound that is produced by stopping Hydrochloric acid in anamount equivalent to the reaction at another point on the viscosityabout 2.8% by weight, based on the rubber, is added and the temperatureis reduced to about A thin Coa ing of a composition containing 175 F. Anamount of anhydrous stannic chloride these resins will give not onlywaterproof charequivalent to about 7% by weight, based on theacteristics to the base film but will also render the rubber is addedand the solution is thoroughly film heat scalable and will reduce thevapor mixed at 175 F. until the viscosity is 0.30 minute transmissionthrough the resulting coated sheet. (Gardner mobilometer) at 25 C. Thereaction is The resulting sheet, furthermore, is non-tacky at thenstopped by the addition of water and the ordinary atmospherictemperatures and condiresulting mass is filtered. The solvent is thenremoved from the mass by steam distillation and The coating compositionof this invention can ,the residual solids are centrifuged, dried and beapplied to sheet materials made of cellulose, milled. The resultingpolymerized end product cellulose derivatives, proteins or materialsderived known as Pliolite is directly suitable for use from proteins .orgelatine. We have found that a in the preparation of the coatingsolutions and casein sheet material hardened with formaldecompositionshereinafter described. 7 hyde is particularly valuable for this purpose.A The coating composition may be produced by disclosure of a method formaking a casein-formdissolving a suitable amount of the reactionprodaldehyde sheet material will be found-in the couct of rubber with anamphoteric metal halide pending application, Serial No. 630,406 ofEdouard described above inbenzol, toluene, naphtha. or other suitableorganic solvents or mil rtuiesttof dition to the advantages mentionedabove, solvents and applying the resulting solu ion 0 e thz rzgctionproducts of rubber with amphoteric sheet material to be treated. Themost suitable metal halides can be dissolved readily in low boilsolventfor this purpose will be determined by its boiling range, which, in turnis determined by the 1 type of coating machine, the speed at which it iswithout the added ingredients. ample of material suitable for thispurpose, we

Benze to be run and the number of seconds which this speed allows forthe drying of the coated sheet material.

When the coating machine is constructed to permit a long drying period,a comparatively high boiling solvent may be used but when only a shortdrying period is permitted a low boiling solvent will be required inorder that the sheet may become sufficiently dry to be non-tacky in thetime allowed for drying period.

As a specific example of this modification of our invention, but not forpurposes of limitation,

. we give the following illustrative formula for our composition:

Parts by weight Reaction product of rubber with an amphoteric metalhalide (Pliolite) I Benzene, toluene, or naphtha 90 It is, however,advantageous to add other in- I gredients to our composition. Forexample,'the

addition of waxes or waxy materials, halogenated fats or oils, orcertain fatty acids, will materially decrease vapor transmission throughthe coat-. ing. Of course, it is to be understood that the reactionproduct of rubber with an amphoteric metal halide will itself materiallydecrease vapor transmission through the coated sheet and for I 'manycommercial purposes is sufficient even As specific ex- .mention,paraifin, petrolatum, ceresin, beeswax, hydrogenated cotton seed oil,hydrogenated lard and stearic acid.

While the coating composition of our invention will adhere to thesurface of ordinary cellulose or protein sheet material in an entirelysatisfactory manner, greater adhesion to the surface may be obtained bythe addition of any natural or artificial gum or resin such as dammar,elemi, spermaceti, cumarone, vinyl resin and chlorinated diphenyl. Asspecific examples of our composition when these materials areincorporated, we

present the following formula:

' Parts by weight Pliolite 10 Chlorinated diphenyl 2 Naphtha 87 Thisformula gives a particularly adherent coating. We attribute this greateradherence to the chlorinated diphenyl. The reduced vapor transmissionexhibited by coatings. made with i this formula is definitely increasedby'the Pliolite. An additional formula showing another modification ofour invention is as follows:

Parts by weight Reaction product of rubber with an amphoteric metalhalide (Pliolite or Plioform) 10 Paraflin 2 Cumarnne 2 Naphtha 43Benzene 43 The cumarone mentioned in the above formula may be omitted ifdesired, but if used it mate- I rially increases the inherence of thecoating to i the base material.

Another modification of this invention is shown Plasticizers may beadded to any or all of the 1 above representative formulae if desired.

The application of the coating solutions of this invention to the sheetmaterial and the preparation of these coating solutions may be carriedout as follows:

The various ingredients of the composition'are dissolved in theorganicsolvent selected. This selection, of course, will depend on theparticular coating equipment and drying facilities available as pointedout above. All of the ingredients disclosed will dissolve in vthesolvents listed and many other volatile inert organic solvents ormixture of solvents which will dissolve these materials are alsosatisfactory. We do not limit ourselves to the particular solvents usedsince obviously any skilled chemist canselect numerous solvents andcombinations of solvents which will be operative in our process.

After the various ingredients have been dissolved and the solventsselected, the solution may be coated onto the sheet material on anymachine ordinarily used for coating. such material.

While we have suggested specific percentages of .the reaction productsof rubber with an amphoteric metal halide in the above illustratedformulas, it will be understood that the concentration of these productsin the solvents can be varied through a wide range depending upon theadjustment of the coating machine and the type of coating desired. Forexample, if, for the particular purpose, the waterproofing and moistureproofing qualities of the composition are not required but it is onlynecessary to provide the sheet material with a superior sheen or finishprovided by our coating material, a very superficial coating willsufli'ce. As little as 1% of the reaction' products of rubber withamphoteric metal halides may be employed under these circumstances.However, if a very substantial coating is required, as much as 20% ofthis material may be used. The upper limit is determined by the abilityof the coating machine to handle the resulting viscous solution. Thethickness of the coating is not determined entirely by the concentrationof the solution. The adjustment of the doctor blades on the coatingmachine also influences this thickness so that it is possible, bysetting the doctor blades to apply but a slight-pressure and use a thinsolution to produce a coating of the same thickness as would result fromapplying more pressure and using a thick solution. l

One of the special'advantages of our invention .is that a large amountof paraffin may be added to the formula without detrimentally affectingthe finished coating in any way.- We find that we may use as much as 20%or ,even more of be obtained very cheaply, the large amounts which weare able to use in our composition decreased the cost of the resultingcoating. The non-blocking property of sheets coated with the coatingcompositions of this invention is a very advantageous feature of ourinvention.

When sheets coated with our composition are piled up together they donotstick or adhere under any ordinary climatic ,conditions as has beenthe case with other coating materials used for this purpose. This is dueto the comparative lack of tackiness and inability to soften underordinary climatic temperatures and moisture conditions. However, as thetemperature is increased materially the product will become suflicientlyplastic to be heat-sealing. This is a great advantage over materialspreviously suggested for this purpose. "The heat-sealing property is notexhibited at temperatures to which the material would commonly besubjected in storage or use.

An additional very desirable property of the products of this inventionis their peculiar and pleasing sheen exhibited on the coated sheets.

We are aware that many changes may be made and numerous details ofconstruction may be varied through a wide range without departing fromthe principle of this invention; and we.

therefore, do not purpose limiting the patent granted hereon otherwisethan necessitated by the prior art.

We claim as our invention:

1. A meltable wax-like composition comprising at least 20% by weight ofwax and the balance composed largely of a condensation derivative ofrubber obtainable by decomposing with water a product obtained bytreating rubber in solution with chlorostannic acid or a halide of anamphoteric metal.

2. A meltable wax-like composition composed largely of paraffin and acondensation derivative of rubber obtainable by decomposing with water aproduct obtained by treating rubber in solution with chlorostannic acidor a halide of an amphoteric metal. I 3. A meltable wax-like compositioncomposed essentially of parafiin and a condensation derivative of rubberobtainable by decomposing with water a product obtained by treatingrubber in solution with chlorostannic acid or a halide-of an amphotericmetal, and containing at least 20% by weight of paraflln.

4. A solution of a wax-like composition which is is composed essentiallyof a common solvent at' least 20 parts by weight of paraffin and up to80 parts by weight of a condensation derivative of rubber obtainable'bydecomposing with water a product obtained by treating rubber in solutionwith chlorostannic acid or a halide of an amphoteric metal.

6. The method of making meltable wax-like compositions which comprisesmixing at least 20% by weight of wax with a condensation derivative ofrubber obtainable by decomposing with water a product obtained bytreating rubber in solution with chlorostannic acid or a halide ofamphoteric metal.

7. The method of preparing solutions of waxlike compositions whichcomprises dissolving ,in a common solvent wax and a condensationderivative of rubber obtainable by decomposing with water a productobtained by treating rubber in solution with chlorostannic acid or ahalide of an amphoteric metal.

8. The method of preparing meltablewaX-like compositions which comprisesdissolving in a common solvent wax and a condensation derivative ofrubber obtainable by decomposing with water a product obtained bytreating rubber in solution with chlorostannic acid or a halide of anamphoteric metal, and then evaporating the solvent.

I MARIE BENEDICT, Administratria: of the Estate of Erich Gebauer-Fuelnegg, Deceased.

' LOUIS K. EILERS.

' EUGENE W. MOFFETT.

